public function getInvalidIsbn13() {
return array(
array(
'1234567890',
),
array(
'987',
),
array(
'0987656789',
),
array(
0,
),
array(
'0-4X19-9261981',
),
array(
'978-0321513774',
),
array(
'979-0431225385',
),
array(
'980-0474292319',
),
array(
'978_0451225245',
),
array(
'978#0471292319',
),
);
}